R1080 Rev 2 February 2019 Bring Back Brookes Jetty Inc / City of … · 2019. 6. 10. · Figure 2.5 Parks Victoria Recreational Boating Guide Extract (2010) Local Nautical Charts

m p rogers & associates pl Brookes Jetty Concept Options K1568, Report R1080 Rev 2, Page (i)

R1080 Rev 2

February 2019

Bring Back Brookes Jetty Inc / City of Port Phillip

Brookes Jetty

Concept Options

www.coastsandports.com.au

m p rogers & associates pl BBBJ Inc & City of Port Phillip, Brookes Jetty Concept Options K1568, Report R1080 Rev 2, Page i

m p rogers & associates pl creating better coasts and ports

Suite 1, 128 Main Street, Osborne Park, WA 6017

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K1568, Report R1080 Rev 2

Record of Document Revisions

Rev Purpose of Document Prepared Reviewed Approved Date

A Draft for MRA review A Clapin P Doust P Doust 10/9/18

0 Issued for Client Use A Clapin P Doust P Doust 14/9/18

1 Updated & Reissued with Client Comments A Clapin P Doust P Doust 6/2/19

2 Updated & Reissued with Client Comments

A Clapin P Doust P Doust

12/2/19

Form 035 18/06/2013

Limitations of this Document This document has been prepared for use by the Client in accordance with the agreement

between the Client and M P Rogers & Associates Pty Ltd. This agreement includes constraints on

the scope, budget and time available for the services. The consulting services and this document

have been completed with the degree of skill, care and diligence normally exercised by members

of the engineering profession performing services of a similar nature. No other warranty,

expressed or implied, is made as to the accuracy of the data and professional advice included.

This document has not been prepared for use by parties other than the Client and its consulting

advisers. It may not contain sufficient information for the purposes of other parties or for other

uses.

M P Rogers & Associates takes no responsibility for the completeness or form of any subsequent

copies of this document. Copying this document without the permission of the Client or

M P Rogers & Associates Pty Ltd is not permitted.

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m p rogers & associates pl BBBJ Inc & City of Port Phillip, Brookes Jetty Concept Options K1568, Report R1080 Rev 2, Page ii

Table of Contents

1. Introduction 4

2. Background Information 6

2.1 Brookes Jetty & Shakespeare Grove Outfall Design 6

2.2 Survey & Navigation 8

2.3 Sediment Movement 10

2.4 Water Levels 10

2.5 Waves 12

3. Jetty Concept Options 13

3.1 Design Criteria for New Jetty 13

3.2 Concept Option 1 - Original Jetty Alignment & Viewing Platform 15

3.3 Concept Option 2 - Increased Jetty Width & Viewing Platform 15

3.4 Concept Option 3 - Increased Jetty Length / Width & Viewing Platform 15

3.5 Other Items 16

3.6 Cost Estimates 17

4. Summary 18

5. References 19

6. Appendices 20

Appendix A Brookes Jetty General Arrangement & Pile Plan 21

Appendix B Shakespeare Grove Outfall Design Drawings 22

Appendix C Concept Option 1 Plan View & Section 23

Appendix D Concept Option 2 Plan View & Sections 24

Appendix E Concept Option 3 Plan View & Sections 25

m p rogers & associates pl BBBJ Inc & City of Port Phillip, Brookes Jetty Concept Options K1568, Report R1080 Rev 2, Page iii

Table of Figures

Figure 1.1 Location Diagram (Nearmap 17 May 2015) 4

Figure 1.2 Brookes Jetty (Nearmap 17 May 2015) 5

Figure 2.1 Brookes Jetty Taken 1920-1950 (St Kilda Historical Society 2015) 6

Figure 2.2 St Kilda Beach Taken 1918-1919 (St Kilda Historical Society 2015) 7

Figure 2.3 Brookes Jetty Taken August 2014 (St Kilda Historical Society 2017) 7

Figure 2.4 Brooks Jetty Head Panorama Photo Taken 2010 (Google Earth

2010) 7

Figure 2.5 Parks Victoria Recreational Boating Guide Extract (2010) 8

Figure 2.6 Extract from Nautical Chart AUS 155 9

Figure 2.7 Extract of Survey Data Surrounding the Brookes Jetty 9

Figure 3.1 Life Saving Victoria Diving Depth Calculator 14

Figure 3.2 Example of Seasonal Floating Pontoon in Rockingham, W.A 17

Table of Tables

Table 2.1 Williamstown Tidal Characteristics (Victorian Regional Channels

Authority 2018) 11

Table 2.2 Projected Sea Level Rise for Planning (Melbourne Water 2017) 11

Table 2.3 Port Phillip Bay Tidal Inundation Levels (Melbourne Water 2017) 12

Table 3.1 Recommended Water Depths (Royal Life Saving 2008) 13

Table 3.2 Concept Level Cost Estimates for Each Jetty Option 17

m p rogers & associates pl BBBJ Inc & City of Port Phillip, Brookes Jetty Concept Options K1568, Report R1080 Rev 2, Page 4

1. Introduction

The Brookes Jetty was originally constructed in the 1880’s by a local fisherman and boat-builder,

Fred Brooke (Garner 2016). The structure was located within Port Phillip Bay, Victoria on the St

Kilda Foreshore between the St Kilda Pier and the St Kilda Marina. Over its long history, the

Brookes Jetty was repaired a number of times and, in around 1934, was rebuilt. It is clear that the

Jetty was highly valued by the community of St Kilda and those who visited the area.

More recently the Brookes Jetty sustained damage from storms including significant damage to

the head of the structure in June 2014 (Garner 2016). Sections of the timber Jetty were

subsequently closed and engineering reports deemed that the structure was unsafe for public use

(City of Port Phillip 2015). Coupled with the Brookes Jetty not meeting the current day

accessibility standards, Parks Victoria who had jurisdiction over the Jetty, decided against

repairing the structure and demolished it in October 2015.

The location of the Brookes Jetty prior to its demolition is shown in the following aerial

photographs.

Figure 1.1 Location Diagram (Nearmap 17 May 2015)

Port Phillip Bay

St Kilda Marina

St Kilda Pier St Kilda

Brookes

Jetty

St Kilda

Harbour


Figure 1.2 Brookes Jetty (Nearmap 17 May 2015)

Since its demolition, a community group called Bring Back Brookes Jetty Inc (BBBJ Inc) has

formed and seek to have the Brookes Jetty rebuilt. BBBJ Inc received funding from the City of

Port Phillip to engage specialist coastal and port engineers, M P Rogers & Associates, to develop

three concept options to replace the Brookes Jetty.

This report presents the three concept options for the Brookes Jetty replacement and

corresponding cost estimates.

Port Phillip Bay

Brookes

Jetty

Shakespeare

Grove Outfall


2. Background Information

2.1 Brookes Jetty & Shakespeare Grove Outfall Design

The Brookes Jetty structure was rebuilt in around 1934 (Garner 2016). However, the extent of the

rebuild and whether the original structure (1880’s) foundations were used, is unclear from the

information available. In any case, the Brookes Jetty that existed until October 2015 was likely

well past its design life, typically 25 or 50 years for similar structures.

There were no design drawings available for the original or rebuilt Brookes Jetty. However, a

general arrangement and pile plan for the Brookes Jetty was provided by Parks Victoria. These

were likely developed for monitoring and maintenance purposes and are provided as Appendix A.

The structure was predominantly timber, including the piles, and included a steel handrail along

one side as well as an electrical conduit underneath the deck that serviced a single lightpole at

the head.

The Heritage Council Victoria recognised the Brookes Jetty as a Heritage Inventory Site

(H7822-0578). However, the Council had no authority regarding the Jetty and it was not subject

to a heritage planning overlay.

The Brookes Jetty extended from the Shakespeare Grove Outfall (refer to Figure 1.2) , a drainage

outlet which still exists today. The structure was originally timber and was reconstructed in the

early 1950’s with sheet piled sides and a concrete platform deck. The structure was again

modified in the 1980’s. Melbourne Water provided available design drawings for the Shakespeare

Grove Outfall, which are shown in Appendix B.

Historical and more recent photographs of the Brookes Jetty and Shakespeare Grove Outfall are

shown in the following Figures.

Figure 2.1 Brookes Jetty Taken 1920-1950 (St Kilda Historical Society 2015)


Figure 2.2 St Kilda Beach Taken 1918-1919 (St Kilda Historical Society 2015)

Figure 2.3 Brookes Jetty Taken August 2014 (St Kilda Historical Society 2017)

Figure 2.4 Brooks Jetty Head Panorama Photo Taken 2010 (Google Earth 2010)

The City of Port Phillip also provided a feature survey that was completed in June 2009 of the

Brookes Jetty, Shakespeare Grove Outfall and adjacent St Kilda Foreshore areas. Spot levels

show that the Shakespeare Grove Outfall platform slopes down to approximately 2 mAHD at the

head where the Brookes Jetty extended from. The Brookes Jetty was offset north of the Outfall


and had a consistent 2 mAHD deck level along its length of around 70 m. The Jetty was

approximately 1 m wide along the main walkway and had a 2.8 x 4.1 m head extending to the

north.

2.2 Survey & Navigation

The Parks Victoria Port Phillip Recreational Boating Guide (2010), in Figure 2.5, shows that the

Brookes Jetty was within a no boating area between the St Kilda Harbour and the St Kilda Marina.

Figure 2.5 Parks Victoria Recreational Boating Guide Extract (2010)

Local Nautical Charts AUS 143 Port Phillip, Victoria and AUS 155 Port of Melbourne, Victoria both

include the St Kilda Foreshore and previous location of the Brookes Jetty. An extract of Nautical

Chart AUS 155 is shown below in Figure 2.6. The resolution however, is limited in enabling

depths near the Jetty to be determined.

Brookes

Jetty


Figure 2.6 Extract from Nautical Chart AUS 155

Available survey data was obtained for the area surrounding the Brookes Jetty, including:

◼ Victorian coastal nearshore bathymetry at 20 m resolution derived from LiDAR taken in

2008 and 2009 (Department of Environment, Land Water and Planning). This dataset was

used to generate the contours shown below in Figure 2.7 for the area that included the

Brookes Jetty.

◼ Spot levels (mAHD) from a St Kilda Marina Hydrographic Survey taken in 2017 (Water

Technology 2018). The spot levels nearest to the Brookes Jetty site are also shown below

in Figure 2.7.

Figure 2.7 Extract of Survey Data Surrounding the Brookes Jetty

Brookes

Jetty


As shown, the surveyed levels vary significantly between the two datasets. The datum for the

Victorian coastal nearshore bathymetry data is also unclear from the accompanying metadata and

there isn’t a consistent difference with the St Kilda Marina Hydrographic Survey to determine a

datum with any certainty.

Given the survey timeframes and resolution of the data, the 2017 spot levels from the St Kilda

Marina Hydrographic Survey are likely more reliable than the 2008 / 2009 Victorian coastal

nearshore bathymetry data. Furthermore, the 2017 spot levels better accord with onsite

observations by members of BBBJ Inc. The discrepancies between the two survey datasets may

be due to sediment movement near the shoreline, discussed further in the following Section 2.3.

Despite likely being more reliable, the St Kilda Marina Hydrographic Survey extent doesn ’t include

the Brookes Jetty or the nearshore area to the north. Updated hydrographic survey will be

required if one of the concept options is to proceed.

2.3 Sediment Movement

The St Kilda Foreshore is bound by the St Kilda Harbour to the north and the St Kilda Marina to

the south, which likely restricts the amount of sediment transporting to and from the shoreline at

this location. Preliminary evidence suggests that around 4,000 m3 of dredging is completed by the

Marina around every 6 to 12 months, which may be pumped onto the beach (pers. comm. Perkins

2018). This would influence the seabed levels at the Brookes Jetty site and may explain the

varying survey information shown in Figure 2.7.

In progressing one of the concept options discussed in Section 3, further investigation and details

of any sand management, including nourishment and dredging, would be required. This, in

conjunction with the updated seabed survey information would inform the design of a new

structure at this location.

Aerial photos also suggest that seasonal changes in weather and flows out of the Shakespeare

Grove Outfall can affect sediment movement and water depths at the site. Further investigation of

this would also be required to progress one of the concept options.

2.4 Water Levels

2.4.1 Tides

The Brookes Jetty was located in Port Phillip Bay, on the St Kilda Foreshore. The tidal regime at

this location is predominantly diurnal with a spring tidal range of around 1 m. A Bureau of

Meteorology tidal gauge is located at Williamstown, on the other side of Port Melbourne,

approximately 5 km from the St Kilda Foreshore. Water levels recorded between 1966 and 2015

at Williamstown were used to determine the key tidal characteristics provided below in Table 2.1.


Table 2.1 Williamstown Tidal Characteristics (Victorian Regional Channels

Authority 2018)

Key Tidal Level Chart Datum (mCD) Australian Height Datum (mAHD)

Highest Astronomical Tide (HAT) 1.04 0.52

Mean Higher High Water (MHHW) 0.94 0.42

Mean Lower High Water (MLHW) 0.64 0.12

Mean Sea Level (MSL) 0.52 0.00

Mean Higher Low Water (MHLW) 0.44 -0.08

Mean Lower Low Water (MLLW) 0.14 -0.38

Lowest Astronomical Tide (LAT) 0.05 -0.48

The tidal regime and tidal levels at the Brookes Jetty site are likely to be similar to those at

Williamstown.

2.4.2 Sea Level Rise

In February 2017, Melbourne Water released Planning for Sea Level Rise Guidelines - Port Phillip

and Westernport Region. The document sets out the specific requirements that apply to

development proposals in areas that will be affected by coastal inundation (storm surge and wave

action) within the Port Phillip and Westernport region.

The guidelines are consistent with the Victorian Coastal Strategy (Victorian Coastal Council 2014)

and the State Planning Policy Framework, in adopting the following projected sea level rise

values.

Table 2.2 Projected Sea Level Rise for Planning (Melbourne Water 2017)

Timeframe Projected Sea Level Rise (m)

Predicted 2040 0.2

Predicted 2100 0.8

2.4.3 Extreme Water Levels

For Port Phillip Bay, the 1% Annual Exceedance Probability (AEP) coastal inundation levels,

which the guideline provides for planning in the region, are presented in Table 2.3. These are

given for the current day, as well as for 2040 and 2100 assuming the projected sea level rise

values given in Table 2.2. The inundation levels are based on the Intergovernmental Panel on

Climate Change Scenario 2, with consideration for the uncertainty associated with predicting sea

level rise and some allowance for wave action (Melbourne Water 2017).


Table 2.3 Port Phillip Bay Tidal Inundation Levels (Melbourne Water 2017)

Timeframe 1% AEP Inundation Level (mAHD)

Current Day (2017) 1.6

Predicted 2040 1.8

Predicted 2100 2.4

2.5 Waves

The wave climate within Port Phillip Bay is comprised of fetch limited waves generated by local

winds blowing across the water surface of the Bay itself. Port Phillip Bay has a large surface area

and local winds have the potential to generate relatively large fetch limited waves around the

shoreline.

At the St Kilda Foreshore where the Brookes Jetty was previously located, the effective fetch

lengths across Port Phillip Bay were determined. The maximum effective fetch length was found

to be approximately 52 km from the southwest direction.

Port Phillip Bay is located within Wind Region A5 as per AS 1170.2-2011 Structural Design Actions

- Wind Actions. The wind speeds listed in the standard, as well as the appropriate multipliers for

terrain height and direction, were used to complete a local hindcast, using the Coastal

Engineering Manual (2006) method.

The results determined that the significant wind wave height during the 100 year ARI event could

be in the order of 1.5 to 2.0 m with a period of around 5 s.

The fetch limited wind waves generated by the 100 year ARI event winds are likely to be

significantly larger than the boat wake waves generated by boats in the nearby boating zone.

A more detailed assessment of waves including wave modelling would be required to undertake

the preliminary or detailed design of the Jetty.


3. Jetty Concept Options

Three concept options for the replacement of Brookes Jetty have been developed from

discussions with BBBJ Inc and considering the background information and design criteria

outlined in Sections 2 and 3.1 respectively. Concept Options 1, 2 and 3 are presented in Sections

3.2, 3.3 and 3.4 respectively and the corresponding cost estimates are provided in Section 3.6.

3.1 Design Criteria for New Jetty

3.1.1 Design Life

A replacement Jetty shall have a design life of 25 to 50 years in the marine environment, typical

for similar structures and in accordance with AS 4997-2005 Guidelines for the design of maritime

structures.

3.1.2 Design Loads

The design loads for a new Jetty include, but are not limited to, the following:

◼ Dead load.

◼ Live load from Jetty users.

◼ Environmental loads for wind, wave, surge and flooding loads in accordance with AS 4997.

◼ Loads from vessel wash.

3.1.3 Diving & Swimming Depth Guidelines

Swimming Victoria and Swimming Australia have adopted the pool depth requirements outlined in

the Aquatic Guidelines - Safe Water Entry for Competitions (Royal Life Saving 2008) for

competitions. The recommended depths from the report are summarised in Table 3.1 below.

Table 3.1 Recommended Water Depths (Royal Life Saving 2008)

Depth Comment

Less than 0.9 m Dive starts should not be permitted

0.9 - 1.0 m Concourse dive (providing concourse is not more than 0.2 m

above the water surface)

1.0 - 1.2 m Concourse or platform dive (providing concourse or platform is

not more than 0.4 m above the water surface)

1.2 m or greater Platform dive (as long as the platform is not more than 0.75 m

above the water surface)

Depths required for recreational diving facilities are less clear and a standard guideline was not

available, especially for diving into tidal waters. Life Saving Victoria provide a Diving Depth

Calculator resource on their website, which is shown below in Figure 3.1


Figure 3.1 Life Saving Victoria Diving Depth Calculator

From Figure 3.1, it appears that recreational diving from a 0.38 m or 0.75 m platform would

require a 1.8 m or 2 m water depth respectively, compared to competitive platforms that only

require a 1 m or 1.2 m depth respectively.

As the water depths change with the tide at this location, it is important to consider the worst case

water depth when the water level is at lowest astronomical tide (LAT), previously given in

Table 2.1 as -0.48 mAHD.

Consideration was given to a potential low level platform to allow swimming or diving from a

replacement Jetty. At the head of the Jetty for the original structure, as well as for Concept

Options 1 and 2, the seabed level is approximately -1.7 mAHD, as given by the 2017 St Kilda

Marina Hydrographic Survey. At LAT, this equates to a water depth of approximately 1.2 m, which

as per Figure 3.1, does not appear to be appropriate for diving. The following issues were also

determined with regard to a low level platform.

◼ A low level platform that allows swimming only and restricts diving would be difficult to

manage and signage alone likely wouldn’t be sufficient.

◼ Swimming and diving would reduce the amenity for users only using the Jetty for

promenading or sightseeing.

◼ The required level for a swimming or diving platform, if feasible at all, would only be useable

at low tides and inundated during mid to high tides or by wave action.

◼ A low level swimming or diving platform would require monitoring and management during

the above conditions that result in overtopping and inundation.

◼ A low level swimming or diving platform would require monitoring and management of

seabed depths to ensure public safety is maintained.

It was discussed with BBBJ and agreed by all that allowing swimming or diving from a

replacement Jetty, via a low level platform, would not be feasible at this location. The concept

options presented in the following section have therefore been developed to allow sightseeing and

promenading only.


3.2 Concept Option 1 - Original Jetty Alignment & Viewing Platform

Concept Option 1 is for a new Jetty with the original Brookes Jetty alignment, approximately 70 m

long and 1.8 m wide to allow for wheelchair access. It also features a 12 m x 2.8 m platform at its

head, facing to the west for viewing sunsets. A plan view and section of this option is provided in

Appendix C.

The advantages and disadvantages of this option are provided below.

Advantages

◼ Provides a Jetty, similar to the original Brookes Jetty, to sightsee and promenade on.

◼ Provides universal access, including for wheelchairs.

◼ Includes a sunset viewing platform with more space for users than the original Brookes

Jetty.

◼ Is the smallest footprint of the 3 options and therefore has the lowest cost.

Disadvantages

◼ Smallest of the 3 options and therefore has less capacity.

3.3 Concept Option 2 - Increased Jetty Width & Viewing Platform

Concept Option 2 is for a new Jetty on a similar alignment to the original Brookes Jetty,

approximately 70 m long. However, it features a wider 2.4 m deck for increased functionality. It

also features a 12 m x 2.8 m platform at its head, facing to the west for viewing sunsets. A plan

view and sections for Concept Option 2 are provided in Appendix D.


Advantages

◼ Provides a Jetty, similar to the original Brookes Jetty, to sightsee and promenade on.


◼ Has increased functionality with a wider deck.


Jetty.

Disadvantages

◼ Has a greater footprint than Concept Option 1 and therefore a slightly higher cost.

3.4 Concept Option 3 - Increased Jetty Length / Width & Viewing Platform

Concept Option 3 is for a new Jetty, approximately 30 m longer than the original Brookes Jetty.

Similar to Concept Option 2, it features a wider 2.4 m deck for increased functionality. Like the

previous 2 options, it also features a 12 m x 2.8 m platform at its head, facing to the west for

viewing sunsets. A plan view and sections for Concept Option 3 are provided in Appendix E.



Advantages

◼ Provides a Jetty, at the location of the original Brookes Jetty, however longer in length.

◼ Has increased functionality with a wider deck.


◼ The alignment features a turn to the west to provide greater clearance from the boating

area.


Jetty.

Disadvantages

◼ Has a greater footprint than Concept Options 1 and 2 and is therefore the most costly.

3.5 Other Items

A replacement Jetty shall be constructed using modern materials to provide good durability and

minimal maintenance in the marine environment. This includes steel piles and a steel SHS frame

with corrosion protection measures such as painting, wrapping or sacrificial anodes. The handrail

for the Jetty shall also be galvanised or painted steel to maximise durability.

An alternative material to timber decking and/or kerbing could be considered for the replacement

Jetty. Fibre Reinforced Plastic (FRP) composites or Replas recycled plastic products have been

used for some similar structures. The capacity of these products would need to be assessed

against the design criteria in detailed design.

Each of the three concept options abut the northern side of the Shakespeare Grove Outfall as per

the original Brookes Jetty. Confirmation of the condition of the Shakespeare Grove Outfall and

liaison with Melbourne Water, who manage the asset, would be required in progressing one of the

concept options. Preliminary consultation between BBBJ Inc and Melbourne Water has indicated

that a Jetty could be built straight out from the Shakespeare Grove Outfall, provided that it doesn’t

interfere with the water flow deflection device situated at the head of the structure. Each of the

Concept Options 1, 2 and 3 could be built immediately out from the existing Shakespeare Grove

Outfall on similar alignments to those shown in Appendices C to E. Consideration of the water

flow deflection device would need to be worked through in preliminary and detailed design and in

consultation with Melbourne Water.

No geotechnical information was available for the site. The geotechnical conditions have a large

impact on the required pile size and embedment into the seabed. A detailed geotechnical

investigation will be required if one of the concept options proceeds to detailed design.

Given that a lower level platform for a replacement Jetty was determined to be unfeasible

(Section 3.1.3), one way to enable swimming and diving nearby would be to install a floating

pontoon. This could be done nearby the new Jetty and has the following benefits:

◼ A pontoon would have an almost constant freeboard that wouldn’t change with the tide.

Therefore, a lesser height above the water could be maintained based on the required

depths for swimming and diving as discussed in Section 3.1.3.


◼ Further to the above point, a floating pontoon would not be fixed a lower level that would be

inundated during mid to high tidal conditions.

◼ The pontoon could be provided on a seasonal basis, depending on the design conditions

determined through preliminary and detailed design. A floating pontoon would not likely

withstand the 100 year ARI 1.5 to 2 m waves outlined in in Section 2.5, however could be

provided during less severe periods such as over summer. MRA have recently been

involved in the design and management of a number of floating pontoons in Rockingham,

Western Australia (refer to Figure 3.2). These are provided on a seasonal basis from

December to March and anchored to the seabed at sufficient depths to allow swimming.

◼ A pontoon could be located optimally to ensure sufficient water depth and within the no

boating area and accessed from the shoreline rather than from a Jetty.

◼ A pontoon could be provided temporarily for special events. For competitive swimming

events for instance, this may enable lesser water depths to be considered as outlined

previously by Figure 3.1.

Figure 3.2 Example of Seasonal Floating Pontoon in Rockingham, W.A

3.6 Cost Estimates

Concept level cost estimates to construct each of the three concept options discussed in Sections

3.2, 3.3 and 3.4 are summarised below.

Table 3.2 Concept Level Cost Estimates for Each Jetty Option

Option Concept Level Cost Estimate

Concept Option 1 - Original Jetty Alignment & Viewing Platform $850,000 - 1,300,000

Concept Option 2 - Increased Jetty Width & Viewing Platform $1,000,000 - 1,650,000

Concept Option 3 - Increased Jetty Length / Width & Viewing Platform $1,500,000 - 2,250,000

Note: 1. Prices exclude fees associated with approvals. Prices include GST.

2. Prices include management and design fees as well as a 20% contingency.

These costs are based on tendered rates for similar marine based works and discussions with

experienced coastal and marine contractors who operate in Victoria.

Floating

Swimming

Pontoon


4. Summary

The original Brookes Jetty was constructed in the 1880’s and repaired or rebuilt a number of times

since (Garner 2016). As a result of more recent damage to the Brookes Jetty in the winter of

2014, the structure was demolished in May 2015.

MRA were engaged by BBBJ Inc who received funding from the City of Port Phillip, to review

available background information and site conditions and present three concept options for the

replacement of the Brookes Jetty.

Background information including the Brookes Jetty and Shakespeare Grove Outfall designs,

survey and navigation, sediment movement, water levels and waves were discussed in Section 2.

Section 3 outlined the design criteria for a new Jetty and presented each of following three

concept options.

◼ Concept Option 1 - A new Jetty with the original Brookes Jetty alignment and a viewing

platform at the head, facing west.

◼ Concept Option 2 - A new Jetty on a similar alignment to the original Brookes Jetty, however

wider for functionality and also with a viewing platform at the head, facing west.

◼ Concept Option 3 - A new Jetty approximately 30 m longer than the original Brookes Jetty

with a turn to the west. This option is also wider for functionality and features a viewing

platform at the head, facing west.

A low level swimming or diving platform was considered for a replacement Jetty, however the

adjacent nearshore seabed levels don’t satisfy the required depths provided by Live Saving

Victoria. As such, the three concept options presented have been developed as sightseeing /

promenading structures to meet the safety requirements of the relevant standards and guidelines.

Each of the concept Jetty options features a viewing platform at the head that is aligned facing

west to enable sunset viewing. This is a great tourism feature for locals and visitors to the area.

The advantages and disadvantages for each concept option were discussed and concept level

cost estimates to build each of the Jetties were provided for the consideration of BBBJ Inc.

A number of items were also recommended for further investigation throughout the preliminary

and detailed design phases.


5. References

City of Port Phillip, 2015. Brookes Jetty Demolition Works. Available at

.

U. S. Army Corps of Engineers, 2006. Coastal Engineering Manual.

Garner, B., 2016. Historic Jetty Demolished. St Kilda News, available at:

.

Melbourne Water Corporation, 2017. Planning for Sea Level Rise Guidelines - Port Phillip and

Westernport Region. Victoria State Government.

Royal Life Saving, 2008. Aquatic Guidelines - Safe Water Entry for Competitions. The Royal Life

Saving Society, Australia.

St Kilda Historical Society Inc, 2015, 2017. Various Articles. Available at

.

Victorian Coastal Council, 2014. Victorian Coastal Strategy 2014. Victoria State Government

Victorian Heritage Database, 2018. Victorian Heritage Database Report - Brooke’s Jetty.

Heritage Council of Victoria.

Victorian Regional Channels Authority, 2018. Vic Tides 2018 - Edition 2. Victoria State

Government.

Water Technology, 2018. St Kilda Marina - Environmental & Coastal Hazard Assessment.

Prepared for the City of Port Phillip.

http://www.portphillip.vic.gov.au/brooks-jetty-works.htmhttp://stkildanews.com/historic-jetty-demolished/http://stkildahistory.org.au/


6. Appendices

Appendix A Brookes Jetty General Arrangement & Pile Plan

Appendix B Shakespeare Grove Outfall Design Drawings

Appendix C Concept Option 1 Plan View & Section

Appendix D Concept Option 2 Plan View & Sections

Appendix E Concept Option 3 Plan View & Sections


Appendix A Brookes Jetty General Arrangement & Pile Plan


Appendix B Shakespeare Grove Outfall Design Drawings


Appendix C Concept Option 1 Plan View & Section

Suite 1, 128 Main StreetOsborne Park 6017Western Australia

t: +61 8 9254 6600f: +61 8 9254 6699

[email protected] and port engineersm p rogers & associates pl CONCEPT OPTION 1 - ORIGINAL JETTY ALIGNMENT & VIEWING PLATFORM

SCALE 1:1000 AT ORIGINAL SIZE

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AutoCAD SHX TextNEW JETTY ON ORIGINAL ALIGNMENT

AutoCAD SHX TextEXISTING SHAKESPEARE GROVE OUTFALL

AutoCAD SHX TextAHD

AutoCAD SHX Text0.52 mAHD HAT

AutoCAD SHX Text-0.48 mAHD LAT

AutoCAD SHX Text2.0 mAHD

AutoCAD SHX TextSTEEL SHS

AutoCAD SHX TextCIRCULAR STEEL PIPE

AutoCAD SHX TextHANDRAIL

AutoCAD SHX TextTIMBER OR COMPOSITE KERBING

AutoCAD SHX TextTIMBER OR COMPOSITE DECKING

AutoCAD SHX TextSECTION

AutoCAD SHX TextB

AutoCAD SHX Text-

AutoCAD SHX Text1:50


AutoCAD SHX TextA

AutoCAD SHX Text-


AutoCAD SHX TextTIE IN TO EXISTING SHAKESPEARE GROVE OUTFALL CONCRETE DECK

AutoCAD SHX TextPORT PHILLIP BAY

AutoCAD SHX TextNO BOATING AREA BOUNDARY

AutoCAD SHX TextJETTY LAYOUT

AutoCAD SHX Text1:1,000

AutoCAD SHX TextTIMBER GIRDER

AutoCAD SHX Text-

AutoCAD SHX TextA

AutoCAD SHX Text-

AutoCAD SHX TextB

AutoCAD SHX TextAHD




AutoCAD SHX TextAPPROX LEVEL FROM ST. KILDA MARINA HYDROSURVEY


AutoCAD SHX TextNSL

AutoCAD SHX Text-1.5 mAHD

AutoCAD SHX TextLEGEND:

AutoCAD SHX TextEXISTING mAHD SPOT LEVEL (ST. KILDA MARINA HYDROGRAPHIC SURVEY 2017)



AutoCAD SHX TextNOTES:

AutoCAD SHX Text1.AERIAL PHOTOGRAPH FROM NEARMAP TAKEN ON AERIAL PHOTOGRAPH FROM NEARMAP TAKEN ON 17 MAY 2015.


AutoCAD SHX TextC

AutoCAD SHX Text-






AutoCAD SHX TextAPPROX LEVEL FROM ST. KILDA HYDROSURVEY


AutoCAD SHX TextNSL



AutoCAD SHX TextAHD


AutoCAD SHX Text-

AutoCAD SHX TextC

AutoCAD SHX TextWEST FACING VIEWING PLATFORM




Appendix D Concept Option 2 Plan View & Sections


t: +61 8 9254 6600f: +61 8 9254 6699

[email protected] and port engineersm p rogers & associates pl CONCEPT OPTION 2 - INCREASED JETTY WIDTH & VIEWING PLATFORM


20100 40 50m30






AutoCAD SHX Text0.1

AutoCAD SHX Text0.4

AutoCAD SHX Text1.9







AutoCAD SHX Text1.2


















AutoCAD SHX TextNEW JETTY




AutoCAD SHX Text-

AutoCAD SHX TextA

AutoCAD SHX Text-

AutoCAD SHX TextB




AutoCAD SHX TextA

AutoCAD SHX Text-



AutoCAD SHX TextB

AutoCAD SHX Text-












AutoCAD SHX TextAHD


AutoCAD SHX Text-

AutoCAD SHX TextC

AutoCAD SHX TextAHD





AutoCAD SHX TextNSL






AutoCAD SHX TextC

AutoCAD SHX Text-








AutoCAD SHX TextNSL



AutoCAD SHX TextAHD











Appendix E Concept Option 3 Plan View & Sections


t: +61 8 9254 6600f: +61 8 9254 6699

[email protected] and port engineersm p rogers & associates pl CONCEPT OPTION 3 - INCREASED JETTY LENGTH / WIDTH & VIEWING PLATFORM


20100 40 50m30






AutoCAD SHX Text0.4

AutoCAD SHX Text1.9







AutoCAD SHX Text1.2


















AutoCAD SHX TextB

AutoCAD SHX Text-



AutoCAD SHX TextC

AutoCAD SHX Text-




AutoCAD SHX TextSHS STEEL






AutoCAD SHX TextNEW JETTY







AutoCAD SHX TextA

AutoCAD SHX Text-









AutoCAD SHX TextAHD




AutoCAD SHX TextAHD

AutoCAD SHX TextAHD




AutoCAD SHX Text-

AutoCAD SHX TextA

AutoCAD SHX Text-

AutoCAD SHX TextB

AutoCAD SHX Text-

AutoCAD SHX TextC




AutoCAD SHX TextNSL


AutoCAD SHX TextNSL












2019-02-12T10:10:33+0800Alex Clapin

2019-02-12T10:27:36+0800Peter Doust

2019-02-12T10:27:52+0800Peter Doust

R1080 Rev 2 February 2019 Bring Back Brookes Jetty Inc / City of … · 2019. 6. 10. · Figure 2.5 Parks Victoria Recreational Boating Guide Extract (2010) Local Nautical Charts

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